Speaker device

ABSTRACT

A loudspeaker device  1  includes an acoustic diaphragm  5  composed of a domed diaphragm  11,  an edge-like diaphragm  13,  and a junctional flat portion  12  which joins those domed and edge-like diaphragms, and a joined portion  23  where an end surface of a bobbin  4  of a voice coil or of a conductive 1-turn ring  3  is stuck and fixed to the junctional flat portion  12  or a reinforcement ring  15;  and the reinforcement ring  15  is stuck and fixed to the junctional flat portion  12  from above or from under, thereby increasing the mechanical strength of the junctional flat portion  12  of the acoustic diaphragm  5.  A loudspeaker device in which unnecessary vibrations are removed and also the quality of acoustic signals is excellent up to high range is provided.

TECHNICAL FIELD

The present invention relates to a loudspeaker device used for audioequipment, video equipment, or various pieces of other equipment, andparticularly to a loudspeaker device in which the strength of ajunctional flat portion of an acoustic diaphragm is increased.BACKGROUND ART

As shown, for example, in FIG. 12, an acoustic diaphragm in aconventional loudspeaker device has a domed diaphragm 121 shaped like adome in the center, and an edge-like diaphragm 129 which is integrallyformed with the domed diaphragm 121 and extending from the circularperiphery of the domed diaphragm 121 using a polymer film, metal or thelike, such that the edge-like diaphragm 129 has a predeterminedcurvature of concavity or convexity or is linear in cross section.

A voice bobbin 122 on which a voice coil 123 is wound is joined to ajunctional portion where the domed diaphragm 121 and edge-like diaphragm129 of an acoustic diaphragm 120 are integrated such that the voicebobbin 122 hangs down, and the voice coil 123 is provided to be capableof oscillating up and down as a driving means in a gap 127 which forms amagnetic space.

A frame that constitutes a loudspeaker includes a ring-shaped magnet 124provided on a disk-like lower surface plate 135 made of metal, acolumnar pole piece 125 erected approximately in the center of the lowersurface plate 135, a ring-shaped upper surface plate 126 made of metalmounted on the magnet 124, and a cylindrical frame 130 with which theouter circumferential edge of the edge-like diaphragm 129 is fixed; andthe voice coil 123 is disposed in the gap 127 formed between the innercircumference of the upper surface plate 126 and the outer circumferenceof the pole piece 125 to constitute an dynamic loudspeaker device.

When an acoustic signal has been input into a signal input line 128 of aloudspeaker device having such structure, the voice coil 123, which isprovided in a magnetic field of the gap 127, generates driving force foroscillating up and down in the gap 127, and emits the acoustic signal byvibrating the acoustic diaphragm 120.

Regarding such a dynamic loudspeaker device as described above, aconventional method of joining the bobbin 122 and the acoustic diaphragm120 is, for example, shown in FIG. 13. FIG. 13 shows an enlarged view ofthe part A in FIG. 12, and one end of the cylindrical bobbin 122 on theopposite side to the side where the voice coil 123 is wound is stuck toa domed diaphragm inner circumferential edge portion 133 of the domeddiaphragm 121 of the acoustic diaphragm 120 with an adhesive 131.

The acoustic diaphragm 120 is provided continuously to a diaphragmperiphery 134, having a curved cross section of convexity or linearcross section, of the edge-like diaphragm 129, through a junctional flatportion 132, which forms a junctional portion vertically bent from thelower end of the domed diaphragm inner circumferential edge portion 133that is bent downward from the periphery of the domed diaphragm 121, andthe diaphragm periphery 134 is fixed to the cylindrical frame 130.

On the other hand, regarding dynamic electromagnetic inductionloudspeakers, one having a structure in which a conductive 1-turn ringis wound instead of the voice coil 123 wound on the bobbin 122, and onehaving a structure in which an upper end of a cylindrical conductive1-turn ring of a uniform diameter is directly stuck to the domeddiaphragm inner circumferential edge portion 133 of the acousticdiaphragm 120 with the adhesive 131 are being proposed.

According to the above-mentioned dynamic loudspeakers or dynamicelectromagnetic induction loudspeakers which are compact and capable ofreproduction up to high range (for example, to 100 kHz), the acousticdiaphragm 120 including the domed diaphragm 121 and the edge-likediaphragm 129 is obtained by being integrally formed with a thin metalsheet of, such as aluminum, titanium, or with a polymer sheet;consequently, the metal sheet or polymer sheet of the junctional flatportion 132 joining the domed diaphragm 121 and the edge-like diaphragm129 becomes thin, because the sheet is stretched in both the directionsof the domed diaphragm 121 and of the edge-like diaphragm 129, which areopposite to each other, when being formed, hence there is aninconvenience in which mechanical strength lowers.

In addition, if the bobbin 122 shown in FIG. 13 or the conductive 1-turnring is stuck to the domed diaphragm inner circumferential edge portion133 and an acoustic signal is input, at a predetermined frequency thedomed diaphragm 121 and the edge-like diaphragm 129 generate vibrationsrespectively whose phase are different by 180 degrees with each other,with the thin, mechanically weak junctional flat portion 132 as a node.On this frequency there has been an inconvenience in which an acousticsignal emitted from the domed diaphragm 121 and an acoustic signalemitted from the edge-like diaphragm 129 cancel out with each other,causing a dip in acoustic pressure. Particularly, if the dip is in theaudible band, there is an inconvenience in which the quality of acousticsignals deteriorates.

Further, at a high frequency of 20 kHz or more, driving force from thebobbin 122 or from the conductive 1-turn ring is absorbed by theadhesive 131 and the mechanically weak junctional flat portion 132, sothat the driving force is not transmitted to the edge-like diaphragm129. Thus, a problem in which the necessary acoustic pressure cannot beobtained at a high frequency of 20 kHz or more remains to be solved.

In order to solve the above problems, the inventors of the presentinvention previously proposed in Japanese Published Patent ApplicationNo. 2001-346291 a loudspeaker device in which the mechanical strength ofthe junctional flat portion 132 is increased by applying the adhesive131 across the overall width of the junctional flat portion 132 of theacoustic diaphragm 120, and fixing the bobbin 122 to the junctional flatportion 132, as shown in FIG. 14.

Moreover, also a case in which a conductive 1-turn ring 141 shown inFIG. 15 is used as a driving means is disclosed in the above-mentionedgazette. In order for the conductive 1-turn ring 141 to diminishelectric resistance thereof, the width t of the end surface thereof ismade larger than that of the bobbin 122. In this case, when the width t′of the junctional flat portion 132, which joins the domed diaphragm 121and the edge-like diaphragm 129, is approximately equal to the width tof the end surface of the conductive 1-turn ring 141, the mechanicalstrength of this part further increases.

As described in detail in the above FIG. 14, if the width t of the endsurface of the bobbin 122 is smaller than the width t′ of the junctionalflat portion 132, reinforcement is required with the adhesive 131;however, in this case, the strength varies depending on the applicationcondition of the adhesive 131.

In addition, to enlarge the width t′ of the junctional flat portion 132to a great extent causes a problem in terms of design. For example, ifthe width t of the conductive 1-turn ring 141 is intended to fit thewidth t′ of the junctional flat portion 132, the magnetic space, namelythe width of the gap 127 needs to be enlarged as well, causing aninconvenience in which acoustic pressure sensitivity is lessened.

The present invention is to resolve the above-mentioned problems, andprovides a loudspeaker device in which a reinforcement ring is joined toa junctional flat portion or in the vicinity of the junctional flatportion of an acoustic diaphragm to increase the strength of thejunctional flat portion, so that vibrations of a domed diaphragm and anedge-like diaphragm that are different in phase by 180 degrees with eachother are removed, and driving force from a driving means such as avoice coil is transmitted to the acoustic diaphragm to obtain theexcellent quality of acoustic signals up to high range.

DISCLOSURE OF INVENTION

According to a loudspeaker device, which is compact and capable ofreproduction up to high range, of the present invention, a reinforcementring is fixed to a flat portion or to the flat portion including thevicinity thereof, where a domed diaphragm in the center and an edge-likediaphragm of a diaphragm used for an dynamic loudspeaker and an dynamicelectromagnetic induction loudspeaker are joined; and an end surface ofa voice coil bobbin or an end surface of a conductive 1-turn ring isstuck to the flat portion of the acoustic diaphragm or of thereinforcement ring to increase the mechanical strength of a flatportion.

According to the loudspeaker device of the present invention, since thejunctional flat portion or the vicinity of the junctional flat portionof the acoustic diaphragm or of the reinforcement ring is reinforcedwith the reinforcement ring, the strength of the mechanically weakjunctional flat portion, which joins the domed diaphragm and theedge-like diaphragm, increases, so that vibrations of the domeddiaphragm and the edge-like diaphragm that are different in phase by 180degrees with each other are removed and driving force from the coilbobbin is transmitted to the edge-like diaphragm, which enablesreproduction to be performed up to high range (to 100 kHz, for example).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional side view showing a first embodiment of aloudspeaker device according to the present invention;

FIG. 2 is an explanatory view showing an operation of FIG. 1;

FIG. 3 is a partly cross-sectional perspective view showing a secondembodiment of a loudspeaker device according to the present invention;

FIG. 4 is a perspective view showing a first embodiment of areinforcement ring used for a loudspeaker device of the presentinvention;

FIGS. 5A and 5B are enlarged sectional side views showing enlargedcross-section of a part C in FIG. 3 and showing other attaching method;

FIGS. 6A and 6B are enlarged cross-sectional views showing enlargedviews of a part D in FIG. 1 and showing other attaching method;

FIG. 7 is a partly cross-sectional perspective view showing a thirdembodiment of a loudspeaker device according to the present invention;

FIG. 8 is a perspective view showing a second embodiment of areinforcement ring used for a loudspeaker device of the presentinvention;

FIG. 9 is a sectional side view showing another construction of a part Bin FIG. 7;

FIG. 10 is a characteristic curve showing the relation between acousticpressure and frequency of a loudspeaker device of the present invention;

FIG. 11 is a characteristic curve showing the relation between acousticpressure and frequency of a conventional loudspeaker device;

FIG. 12 is a sectional side view of a conventional loudspeaker device;

FIG. 13 is an enlarged sectional side view of a part A in FIG. 12;

FIG. 14 is an enlarged sectional side view showing another constructionof the part A in FIG. 12; and

FIG. 15 is an enlarged sectional side view showing further anotherconstruction of the part A in FIG. 12.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, each embodiment of a loudspeaker device of the presentinvention is explained referring to drawings. FIG. 1 is a sectional sideview in which the present invention is applied to a dynamicelectromagnetic induction loudspeaker, and FIG. 2 shows an equivalentcircuit of the dynamic electromagnetic induction loudspeaker shown inFIG. 1.

In FIG. 1, a loudspeaker device 1 includes a frame portion, an acousticdiaphragm and a driving means.

As regards the frame, a columnar pole piece 2 whose diameter is smallerthan that of a lower surface plate is integrally formed with a lowersurface plate 2 a formed of a disk-like metal and is erectedapproximately in the center of the lower surface plate 2 a, and aconcentric magnet 6 is joined to the lower surface plate 2 a to surroundthe outer circumference of the pole piece 2.

Further, a disk-like metal upper surface plate 7 concentrically formedis joined onto the magnet 6. The frame portion is constructed bycombining a cylindrical frame 10, which has been fitted around theperiphery of the upper surface plate 7, with the upper surface plate 7.

As described later on, an acoustic diaphragm 5 includes a convex domeddiaphragm in the center and an edge-like diaphragm such that theedge-like diaphragm has a curvature R in cross section or is linear fromthe periphery of the domed diaphragm.

As regards the driving means of the electromagnetic induction typeloudspeaker, when a primary excitation coil 3 a insulated and wound onthe pole piece 2 or on a disk-like pole piece plate (not shown in thefigure) fixed on the pole piece 2 and a conductive 1-turn ring 3 fittedto the inner circumference of a bobbin 4 hanging down from anlater-described junctional flat portion of the acoustic diaphragm 5 in agap 8 formed along the inner circumference of the upper surface plate 7are disposed opposing each other to be capable of electromagneticinduction, and a driving current such as an acoustic input signal isapplied through a signal input line 9, an electric current flowingthrough the primary excitation coil 3 a changes, causing a magneticfield by the magnet 6 and by the primary coil excitation 3 a to change,so that an induction current flows through the conductive 1-turn ring 3,and the conductive 1-turn ring 3 oscillates up and down because ofelectromagnetic power, as a result making the acoustic diaphragm 5vibrate correspondingly.

FIG. 2 shows an equivalent circuit of an inductive portion of thedynamic electromagnetic induction loudspeaker shown in FIG. 1; when anvoltage V₁ equivalent to an acoustic input signal is applied to aresistance R₁ and an inductance L₁ on the primary side of an inputimpedance Zin which are equivalent to the primary excitation coil 3 ashown in FIG. 1, an electric current I₁ flows, and an electric currentI₂ equivalent to an output signal flows through a resistance R₂ and aninductance L₂ on the secondary side which are equivalent to theconductive 1-turn ring 3 by means of induction by a mutual inductance M,so that the driving force for oscillating conductive 1-turn ring 3 upand down is generated, thereby making an acoustic signal emitted fromthe acoustic diaphragm 5.

Hereinafter, a method for attaching an acoustic diaphragm and a drivingmeans will be explained, using FIGS. 3 through 6.

FIG. 3 is a perspective view in which part of an acoustic diaphragm 5and part of a conductive 1-turn ring that is a driving means are shownin cross section, and including the same driving means (conductive1-turn ring only) as shown in FIG. 15; and the acoustic diaphragm 5 isconstructed as a single unit by pressing and processing a metal materialsuch as a sheet-like material of aluminum, titanium or the like, or asheet-like material made of a polymer material, and includes anapproximately hemispherical domed diaphragm 11 in the center thereof, ajunctional flat portion 12 continuing from the outer circumference ofthe domed diaphragm 11, an edge-like diaphragm 13 continuing from theouter circumference of the junctional flat portion 12 and having anapproximately arc-shaped or straight-line cross section, and a diaphragmperiphery 14 constituting an edge attached to a cylindrical frame 10formed continuously from an outer circumference of the edge-likediaphragm 13.

The junctional flat portion 12 which joins the above-mentioned domeddiaphragm 11 of the acoustic diaphragm 5 and the edge-like diaphragm 13includes, as shown in FIGS. 5A and 5B, a ring-shaped domed diaphragminner circumferential edge portion (hereinafter described as innercircumferential portion) 12 a, which extends and hangs down from theouter circumference of the domed diaphragm 11; a flat portion 12 bextended in the horizontal direction at the bottom edge of the innercircumferential portion 12 a; and the edge-like diaphragm 13continuously formed at the end edge of the flat portion 12 b.

When integrally formed by means of a press processing, the flat portion12 b of the above-mentioned junctional flat portion 12 is stretched inboth the directions of the domed diaphragm 11 and of the edge-likediaphragm 13, thereby being thinly pressed.

Further, in an dynamic electromagnetic induction loudspeaker, as a coilon the secondary side that is a driving means, the conductive 1-turnring 3 as shown in FIG. 3 and FIGS. 5A and 5B, or the bobbin 4, on aninner circumference of which a conductive 1-turn ring 3 is attached asshown in FIG. 1 and FIGS. 6A and 6B is joined to the lower surface ofthe flat portion 12 b with an epoxy resin adhesive 16. In order tolighten the vibration system, the above bobbin 4 and conductive 1-turnring 3 are made of an extremely light sheet that is as thin as possible.Thus, the thickness of the end surface of the bobbin 4 or that of theconductive 1-turn ring 3 is smaller than the width of the flat portion12 b of the junctional flat portion 12, so that an reinforcingeffectiveness cannot be obtained at one end surface of the bobbin 4 andat that of the conductive 1-turn ring 3 joined to the flat portion 12 bby the adhesive 16.

Accordingly, in the present invention, as shown in FIGS. 3 through 6,the flat portion 12 b is reinforced, using such a reinforcement ring 15as shown in FIG. 4, regarding the junctional flat portion 12.

Specifically, with the width w of the reinforcement ring 15 shown inFIG. 4, which is formed of an aluminum, titanium, polymer or othersheet, or of paper or the like, fitting to the width of the flat portion12 b of the junctional flat portion 12 shown in FIGS. 3 and 5A and FIGS.1 and 6A, the reinforcement ring 15 is stuck and fixed to the junctionalflat portion 12 which forms a depression shaped like a concave groovewith the adhesive 16 or the like in between, thereby increasing themechanical strength of the junctional flat portion 12. The material ofthe reinforcement ring may be the same as that of the acoustic diaphragm5 and may be otherwise. If the material used is the same as that of theacoustic diaphragm 5, it is desirable that the thickness thereof begreater than that of the acoustic diaphragm 5. If the material used isdifferent from that of the acoustic diaphragm 5, such thickness withwhich the strength of the adhered part is twice or more greater thanthat of the material of the acoustic diaphragm 5 is desirable.

At the flat portion 12 b of the junctional flat portion 12 shown inFIGS. 5B and 6B, the reinforcement ring 15 shown in FIG. 4 is joined tothe flat portion 12 b of the junctional flat portion 12 from under (fromthe bottom side of) the flat portion 12 b with the adhesive 16 inbetween, and further, one end of the conductive 1-turn ring 3 or one endof the bobbin 4 on which the conductive 1-turn ring 3 is attached isjoined to the reinforcement ring 15 with the adhesive 16 in between.

In FIGS. 5A and 5B and FIGS. 6A and 6B, such a case in which thereinforcement ring 15 is joined to the flat portion 12 b of thejunctional flat portion 12 from above or from under has been explained;however, it should be noted that both from above and from under areinforcement ring 15 of a predetermined thickness made of apredetermined kind of material may be joined to reinforce the flatportion 12 b.

In addition, as a driving means of a loudspeaker, an electromagneticinduction type loudspeaker has been explained; however, as shown in FIG.12, it should be noted that the present invention can obviously beapplied to a dynamic loudspeaker as well, in which a voice coil is woundaround a conventional bobbin.

Further, another construction of the present invention will beexplained, using FIGS. 7 through 9. FIG. 7 is a partly cross-sectionalperspective view showing a diaphragm and bobbin of another constructionwhen the present invention is applied to an dynamic loudspeaker; FIG. 8is a partly cross-sectional perspective view showing anotherconstruction of a reinforcement ring used for the present invention, andFIG. 9 is a sectional side view showing another construction of the partB in FIG. 7.

As shown in FIG. 9, a reinforcement ring used in this embodiment isjoined from above or from under to: an inner circumferential portion 12a and a flat portion 12 b of a junctional flat portion 12, a partlycurved surface where the edge of the flat portion 12 b extends along anedge-like diaphragm 13, and a partly curved surface where the uprightperiphery of the inner circumferential portion 12 a of the junctionalflat portion 12 extends along a domed diaphragm 11, of an acousticdiaphragm 5.

Specifically, regarding a reinforcement ring 15 a, as shown in FIG. 8,an inner joined ring portion 17 and an outer joined ring portion 18,which are joined to part of the curved surface of the edge-likediaphragm 13 and part of the curved surface of the domed diaphragm 11from above or from under, are integrally formed with a press processingor the like such that a joined portion 23 having a concave cross sectionis provided continuously at a reinforcement ring upright portion 21 anda reinforcement ring flat portion 20.

The reinforcement ring 15 a as described above is stuck and fixed to theflat portion 12 b, the inner circumferential portion 12 a, and part ofthe domed diaphragm 11 and edge-like diaphragm 13 from under thejunctional flat portion 12 with an adhesive 16 in between, as shown inFIG. 7.

Alternatively, as in FIG. 9, the reinforcement ring 15 a is joined fromabove the junctional flat portion 12, with the adhesive 16 to thereinforcement ring flat portion 20. At the time of this joining,adhesive may be evenly applied to the joined portion 23 on the outside(on the bottom surface side) of all the portions including the innerjoined ring portion 17, the reinforcement ring upright portion 21, thereinforcement ring flat portion 20 and the outer joined ring portion 18.

According to the above-mentioned construction of FIGS. 7 through 9, thereinforcement ring 15 whose width is equal to that of the junctionalflat portion 12 is stuck and fixed to the junctional flat portion 12 andalso in the vicinity thereof, and a bobbin 4 is fixed to the lowersurface of the junctional flat portion 12 and the reinforcement ringflat portion 20, so that the mechanical strength of the junctional flatportion 12 and the vicinity thereof increases. The material of thereinforcement ring 15 a may be the same as that of the acousticdiaphragm 5 and may be otherwise. If the material used is the same asthat of the acoustic diaphragm 5, it is desirable that the thicknessthereof be greater than that of the acoustic diaphragm 5. If thematerial used is different from that of the acoustic diaphragm 5, thethickness with which the strength of the part adhered becomes that oftwice or more the thickness of the material of the acoustic diaphragm 5is desirable.

In the above embodiment, a case in which the acoustic diaphragm 5 hasbeen formed in advance and then the reinforcement rings 15 and 15 a arejoined to the diaphragm has been explained; however, it should be notedthat laminating pressing may be simultaneously performed at the timewhen an acoustic diaphragm is formed. Needless to say, reinforcementrings may be respectively joined both from above and from under thejunctional flat portion 12 of the acoustic diaphragm 5.

Hereinafter, differences in characteristics between the presentinvention and a conventional device will be explained, usingcharacteristic curves of FIGS. 10 and 11 showing the relation betweenacoustic pressure and frequency.

FIG. 10 shows the calculation result of the characteristic of therelation between acoustic pressure and frequency of the dynamicelectromagnetic induction loudspeaker explained in FIG. 6A by means ofthe finite element method. The calculation is executed with the width wof the junctional flat portion of the acoustic diaphragm 5 being 0.25mm, while the thickness w′ of the bobbin 4 for a conductive 1-turn coilis 0.05 mm, using the same material and thickness as those of theacoustic diaphragm 5 with respect to the reinforcement ring 15. In FIG.10, acoustic pressure level (dB) is plotted on the vertical axis againstfrequency from 10 kHz to 100 kHz on the horizontal axis.

According to the above-described characteristic of the relation betweenacoustic pressure and frequency, an approximately flat frequencycharacteristic is obtained from 10 kHz to 100 kHz; large level decreasein acoustic pressure are not seen at 40 kHz or under in comparison withan later-described conventional construction; and driving force from thebobbin 4 is efficiently transmitted to the edge-like diaphragm 13without causing phase inversion or the like.

Further, in a similar calculation of the characteristic of the relationbetween acoustic pressure and frequency of the loudspeaker explained inFIG. 7 by means of the finite element method, approximately the sameresult is obtained concerning the characteristic curve showing therelation between acoustic pressure and frequency.

In this case, the calculation is executed with the material and thethickness of the reinforcement ring 15 a that reinforces the junctionalflat portion 12 and the vicinity thereof of the acoustic diaphragm 5being the same as those of the diaphragm. The inner joined ring portion17 and the outer joined ring portion 18, which are reinforcing portionsin the vicinity of the junctional flat portion, are 1 mm in width. Thewidth of the junctional flat portion 12 and the thickness of a voicebobbin are the same as those used in the calculation in FIG. 10. In thiscase also, it has been confirmed that large decrease in acousticpressure at around 40 kHz are not seen, driving force from the voicebobbin is transmitted to the edge-like diaphragm and is efficientlyconverted to audio output similarly to the case of FIG. 10, and decreasein the acoustic pressure level in the range of 40 kHz to 100 kHz isimproved in comparison with the reinforcement ring 15 shown in FIG. 4.

FIG. 11 shows the calculation result of the characteristic of therelation between acoustic pressure and frequency of the loudspeakerexplained in FIG. 14 by means of the finite element method. This is acase in which the width of the junctional flat portion 132 is 0.25 mm,while the thickness of the bobbin 122 is 0.05 mm, which is considerablysmaller. Sharp decrease in acoustic pressure is observed at 40 kHz ormore. In this case, since the strength of the junctional flat portion132 is insufficient, driving force provided by the bobbin 122 can not betransmitted satisfactorily to the edge-like diaphragm 129 at a highfrequency 40 kHz or more, and therefore conversion from the acousticdiaphragm 120 to sound output can not be performed efficiently.

In the above-described construction, a case in which the reinforcementring 15 shown in FIG. 4 and the reinforcement ring 15 a shown in FIG. 8are separately joined to the junctional flat portion 12 of the acousticdiaphragm has been explained; however, needless to say, thereinforcement rings 15 and 15 a may be joined to the top and bottom ofthe junctional flat portion 12 or be combined into a single entity oftriple structure.

According to the loudspeaker device of the present invention, areinforcement ring is joined from above or from under a junctional flatportion or the vicinity thereof of a diaphragm having a junctional flatportion joining a domed diaphragm and an edge-like diaphragm in order toincrease the strength, and driving means such as a voice coil is joinedto the junctional flat portion or the junctional flat portion and thevicinity thereof and to the reinforcement ring, so that the mechanicalstrength of the junctional flat portion increases; unnecessaryvibrations are removed; production is facilitated in comparison with thecase in which adhesive is applied; conversion to sound output can beperformed efficiently; and an dynamic loudspeaker device capable ofreproducing up to high range of 100 kHz in an approximately flat mannercan be obtained.

INDUSTRIAL APPLICABILITY

According to the present invention, as described above, the loudspeakerdevice can be provided as a loudspeaker suitable for a tweeter or thelike, in which the quality of acoustic signals is excellent up to highrange in a loudspeaker system.

1. A loudspeaker device, comprising: a diaphragm in which a domed diaphragm and a junctional flat portion that joins an edge-like diaphragm are integrally formed; driving means provided in a magnetic space to drive said diaphragm; and a reinforcement ring that reinforces said junctional flat portion or the vicinity of said junctional flat portion of said diaphragm, wherein said driving means is joined to a joined portion at which said reinforcement ring is joined to said junctional flat portion or the vicinity of said junctional flat portion of said diaphragm.
 2. A loudspeaker device according to claim 1, wherein one end of a bobbin with a voice coil that constitutes said driving means being wound thereon is fixed to said joined portion.
 3. A loudspeaker device according to claim 1, wherein one end of a conductive 1-turn ring that constitutes said driving means is fixed to said joined portion.
 4. A loudspeaker device according to claim 1, wherein one end of the bobbin with the conductive 1-turn ring that constitutes said driving means being attached thereto is fixed to said joined portion.
 5. A loudspeaker device according to claim 1, wherein said reinforcement ring is a flat-plate shaped ring joined to the inside of a depression that constitutes said junctional flat portion of said diaphragm.
 6. A loudspeaker device according to claim 1, wherein said reinforcement ring is a flat-plate shaped ring joined to the outside of the depression that constitutes said flat portion of said diaphragm.
 7. A loudspeaker device according to claim 1, wherein said reinforcement ring is a flat-plate shaped ring joined to the inside and outside of the depression that constitutes said flat portion of said diaphragm.
 8. A loudspeaker device according to claim 1, wherein said reinforcement ring includes an annular ring, part of which extends along said domed diaphragm or said edge-like diaphragm.
 9. A loudspeaker device according to claim 1, wherein said reinforcement ring and said junctional flat portion of said diaphragm are integrally formed.
 10. A loudspeaker device according to claim 8, wherein an annular rib disposed on the inner circumference of a depression that constitutes said flat portion of said diaphragm, part of which extends along said domed diaphragm and said edge-like diaphragm, is provided on the inner circumference of said flat-plate shaped ring.
 11. A loudspeaker device according to claim 8, wherein an annular rib disposed on the outer circumference of a depression that constitutes said flat portion of said diaphragm, part of which extends along said domed diaphragm and said edge-like diaphragm, is provided on the outer circumference of said flat-plate shaped ring. 